Electrochemical reformation of levulinic acid and short-chain aliphatic acids and electrochemical polymerization of dicarboxylic acids.

摘要

Electro-oxidation of levulinic acid (LA) and electrochemical reformation of LA and short-chain aliphatic acids into value-added chemicals such as: 2,7-octanedione, C6-C10 n-alkanes, C7-C9 2-alcohols, C7-C9 2-alkanones and hydrogen gas are reported. A cyclic voltammetry (CV) study indicated that the electro-oxidation of LA in MeOH using a Pt anode proceeded by an electrochemical-chemical (EC) mechanism. The keto- group of LA increased the oxidation potential and decreased the mobility of levulinate ion, and raised the oxidation potential of the radical-to-carbocation transformation. The keto- group also increased the polarity of LA so as to reduce its ability to compete with H2O molecules for the electro-oxidation.;Electro-synthesis of a novel liquid triketone, 5-acetyl-2,9-decanedione (TK) [n35d =1.4524, T m 200 °C], a molecule that has a "Y" structure with a carbonyl group anchored at the end of each arm is reported. TK is formed through the electrooxidation LA in a MeOH/H 2O system. The possible mechanism of formation of TK via a side reaction of Kolbe electrolysis is proposed. Theoretical analysis of the TK coordination with lithium ions, forming bidentate Li+(TK) Li-O1O2, or Li+(TK)Li-O2O3 or tridentate Li +(TK)Li-O1O2O3 complexes was conducted. The results suggest that one TK molecule can complex two Li+. Thus, TK might be applied as a cosolvent for lithium ion batteries.;The electropolymerization of aliphatic and aromatic dicarboxylic acids (HOOC-RCOOH) into polyethylenes / polyesters was explored. The mechanism of the polymerization was investigated using CV and computational modeling. The results showed that the oxidation of HOOC-R-COO- substrate proceeded by an EC mechanism. The main chain extension reaction in the electropolymerization of aromatic isophthalic acid was the formation of an ester linkage between ~R-COO• and ~R• radicals. A one-pot synthesis of polyesters containing various ratios of aliphatic and aromatic moieties was demonstrated by electro-copolymerization of aliphatic adipic acid and isophthalic acid.;FT-IR, 1H-, 13C-, 2D and solid-state 13C NMR, GC-MS, TGA, Py-MS, GPC, and computational modeling were used to identify and characterize these chemicals and polymers.